Paul minnis



(No Model.)

P. MINNIS.

LINE JACK EUR TELBPHONIG SWITGHBOARDS'. No. 561,420. Patented June 2Q1896.

` j iwf j W M 97W UNTTED STATES PATENT Ormes".

PAUL MINNIS, OF MOBILE, ALABAMA, `ASSIGrNOR OF ONE-HALF TO THE HOMETELEPHONE COMPANY, OF SAME PLACE.

LINE-JACK FOR TELEPHoNlC swlTeHBoARDs.-

SPECIFICATION forming part of Letters Patent No. 561,420, dated J une 2,1896. Application fired rebruaryiv, i896. Seriana. 679,648. (romeni.)

.To all whom it may concern:

Be it known that I, PAUL MINNAIS, a citizen of the United States,residing at Mobile, in the county of Mobile and State of Alabama, haveinvented new and useful Improvements in Line-Jacks for TelephonieSwitehboards, of which the following is a specification.

My invention relates to line-jacks for telephonic switchboards ,mypurpose being to provide a construction whereby the insertion of a plugconstructed in harmony with the linejack shall have the effect ofopeningthe callcircuit between the corresponding line-sta tion and the centralstation, switching in the communicating wires or service-wires whichconnect the line-stations with the central station and with a commonreturn-wire, and finally completing a circuit which restores a visualcall-signal at the central station to its normal position, in readinessto respond to the next call from the line-station.

It is my purpose, also, to combine with a line-jack of the kindspecified a plug having such construction that it shall cooperate withthe jack and its contacts in producing the results mentioned, and havingsuch an organization that two separate wires entering the plug may becoupled electrically at any moment by a simple, slight, and rapidmovement of the finger of the operator and again separatedautomatically, whereby the operators head-phonemay be cut in and out.

My invention also comprises other novel features, all of which will befully explained hereinafter and then particularly pointed out anddefined in the claims which complete this specification.

To enable those skilled in the art to which my invention pertains tofully understand and to practice the same, I will now describe saidinvention in detail, reference being made for this purpose to theaccompanying drawings, in which- Figure l. is a central longitudinalsection of a line-jacl constructed in accord ance with my invention.Fig. 2 is a central longitudinal section of the same, the section-planebeing at an angle with that in Fig. l. Fig. 3

is a similar section with a further an gularity of the section-plane.Fig. 4lis a cross-section in the line 4E 4:, Figl. Fig. 5 is atransverse section taken in the line 5 5, Fig. 3. Fig. 6 is a centrallongitudinal section of the plug.

In saidrdrawings the reference-minieral l denotes one of the line-jacksof the switch-` board. It is formed of a substantially cylindrical bodyof insulating material of any suitable kind, having an opening for theinsertion of the plug. The mouth of this opening is provided with abushing 2 and faceplate 3, the bushing being screwed into the opening.

Connected electrically to the faceplate 3 is a conducting-strip 4L,lying in a longitudinal channel 5 in the exterior face of the body l andextending a little beyondits rearward end. In the interior is aconductor 6, also in touch with the face-plate and extending rearwardtill it meets the end of a slot 7, cut longitudinally through from theexterior and extending to a point a little distance from the rear end ofthe jack.

In the slot 7 lies a spring-contact S, fas tened at one end by a screw 9at the rearward end of the jack, its free end passing into the openingbeyond the forward end of the slot 7 and lying opposite the conductor6,from which it is normally separated. Upon the same rearward portion ofthe jack are also mounted two contacts l0.. and l2, lying opposite eachother and passing through slots 13 into the interior, theiroppositely-eurved ends lying normally in electric'contact, but capableof being separated by the entrance of the plug. The line-jack is alsoprovided with two contacts 14 and l5, also mounted on the rear end andlying partly in slots 1G and partly in the opening for the plug. Thesecontacts are never in contact, their oppositely-curved ends beingseparated by an interval somewhat less than the diameter of the plug.All the contacts point toward or have their free ends nearest to theopen end of the jack where the plug enters` The free end of the contact8 lies nearest the open entrance end, andthe two closed contacts 9 andl0 meet at a point between the free end of the contact S and thecontacts 14 and 15.

The conducting-strip 4is connected by wire,

as are the contacts S, 10, and 12, and 11i and 15, to the severalcircuits and multiples of the switchboard. The contact 8 forms part ofthe talkin g-circuit, the two closed contacts 10 and 12 form part of acall-circuit, and the two open contacts 14: and 15 are parts of acircuit which restores the call-signal to its normal or originalposition.

The reference-numeral15 indicates the conducting tubular body of one ofthe plugs, in one end of which is inserted the shank 19 of anon-conducting point 20, slightly larger than the tubular body. Betweenthe end of the latter and a metallic tip 21 the non-conducting point isexposed, and between the enlarged non-eonductin g point and a sleeve 22of non-conducting material covering the tubular body the conductingmetal 18 is exposed. Excepting this exposed portion 1S and the lnetaltip 21 the conducting-body is covered by the sleeve 22, on which isformed a collar 23 to limit the extent to which the plug is inserted inthe line-jack.

Upon the open end of the sleeve and tubular body a cap 24 is mounted,having slots 25, through which screws 26 are tapped into the sleeve andbody 18. These slots permit a limited longitudinal movement of the cap,which is normally pressed outward by a springl27, coiled inside the cap.

`lVithin the tubular body 1S is a metal core 2S., to which is attachedone of the wires 29 of the flexible cord. In the head of the cap 2i isa' metal ring 30, inclosing a bushing 31, the ends of the sameprojecting into the cap and outside the head of the latter, the exteriorportion being inclosed and protected by a lling 32. rl` he second wireof the leXible cord is connected to this bushing and rino'. By pushingthe cap 24 inward the bushing and ring are caused to engage the end ofthe metallic body, thereby coupling the wires electrically. Thisarrangement is especially adapted for cutting the head-phone of theoperator or a magneto-generator at a central station into and out of thetalking-circuit.

Then inserted in the line-jack, as shown in dottedv lines in Figs. 1, 2,and 3, the contact 8 rests on the exposed part of the conducting-body1S, thus making connection between the service-wire attached to contactS and wire 29 of the iexible cord, and the free end of contact S ispressed against conductor o', thus establishing a test-circuit throughbushing 2, face-plate I5, contact-strip 4i, the test multiple wire, andmultiples of contactstrip 4 to the face-plates of the correspondingjacks of the switchboard. The two contacts 10 and 12 are separated andrest upon the exposed non-conducting point, thereby opening thecall-circuit. Finally, the metallic tip of the plug presses against thecontacts 11 and 15, and thereby completes a circuit which restores thecall-signal to its normal position.

The plug and line-jack described form part of an application iiled byme, of even date herewith, for a telephone-switchboard.

What I claim is- 1. The combination with a telephone-switchboard of aline-jack consisting of a cylindrical body of non-conducting material, aconducting face-plate and bushing an exterior and an interior conductorin electrical contact with the bushing, a single springcontact enteringthe opening for the plug through a slot in the non-conducting body ofthe jack, its free end normally separated from the interior conductor,two opposite springcontacts entering said opening and having free endsnormally in electrical contact, their points being turned toward themouth of the plug-opening, and a pair of separated contacts alsoentering the said plug-opening, a plug having a metallic tip to engagean couple the latter contacts when the plug is inserted, anon-conducting point on said plug to separate and break the electricalcontact between the closed spring-contacts and an exposed conductingportieri on the plug behind the non-conductin g point, to engage thesingle spring-contact electrically and press it against the interiorcontact of the jack when the plug is inserted in the jack, substantiallyas described.

2. A line-jack for telephone-switchboards,

comprising anon-conducting body having an opening for the plug, twoseparated contacts, two normally-closed spring-contacts and a singlespring-contact, all insulated from each other and rigidly attached atone end to the outer face of the non-conducting body, and all enteringthe opening for the plug in the jack through longitudinal slots in thenonconducting body, in combination with a plug having a metal tip toengage and electrically connect the separated contacts, a non-conductingpoint to separate the two closed contacts, and a metallic body having anexposed portion to electrically engage the single contact, and couple itwith the wire of the cord, and with an interior conductor in the jack,substantially as described.

3. In a telephone-switchboard, the combination with a line-jack, havinga non-conducting body provided with an opening for the plug, twoseparated contacts, two normally-closed contacts,and a single contact,all attached at one end to the outer face of the non-conducting body andentering the plugopening through slots, of a plug having a nonconductingpoint to separate the closed contacts, a metallic tip to electricallyconnect the separated contacts and a conducting-body to electricallyengage the single contact and press its free end against an interiorcontact which is engaged with a face-plate, bushing, and exteriorcontact, the rest of the body being covered by a non-conducting sleeve,a cap mounted on the open end of the body, a

IOO

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spring pressing said Cap o the sleeve, t Wire iny hand in presence oftwo subscribing witeonneeted to the condnetingbody, and a seenesses.

0nd wire connected to :t eontaeterino in the T esp, the latter being`capable of engatging the PAUL MINA IS' 5 metal body portion by pressing`the eftp in* Witnesses:

Ward, substantially as described. CLAYTON B. CLARK,

In testimony whereof I have hereunto set WILLIAM H. SULLIVAN.

